The extracellular matrix (ECM) is known to both interact with tumor and stromal cells and mediate their interactions with one another, with significant implications for disease progression and response to therapy. The cover depicts multicolor immunofluorescence of MCF7 breast cancer cells cultured inside a fibroblast-derived, decellularized ECM scaffold. The scaffold contains fibrillar ECM proteins including collagen I (green) and fibronectin (red). Cancer cells were stained with DAPI (DNA – blue) and Phalloidin (F-actin – cyan). Using this model, the authors demonstrated that breast cancer cells receive cues from both the ECM fibers and other bound growth factors with significant implications for estrogen receptor activity and response to antiestrogens. For more information, see the Highlight on page 1 and the article on page 136.